The present invention relates to control apparatus and more particularly to apparatus for controlling the movement or positioning of a control member.
Many types of devices or articles must be accurately and finely controlled in a desired manner and to a desired degree in order to function properly. Often this desired control is accomplished by relative positioning of a control member in or with respect to the device or article which the control member is to control. That is, the positioning of the control member relative to the workpiece effects the desired control. Further in such arrangements, finely controlled positioning or adjustment of the control member will often effect control to a very fine degree.
For example, the size or opening of a flexible tube may be controlled by compressing, to different degrees, the tube to thereby control the amount of fluid flowing through such tube. This can be achieved by compressing the tube between a control member and a stationary support so that the distance between the end of the control member engaging the tube and the support for the tube is indicative of the size of the opening of the tube. Thus, by controlling to a very fine degree the positioning of the control member relative to the tube support, the size of the tube opening, and thus the amount of fluid flowing therethrough, may be controlled and adjusted to a correspondingly fine degree.
Accordingly, for these and other reasons, it is desirable to be able to finely control or adjust the positioning of a control member.